Automatic gain control for communications demodulation in wireless power transmitters

ABSTRACT

A wireless transmission system includes a transmitter antenna, a sensor, a demodulation circuit, and a transmitter controller. The sensor is configured to detect electrical information superimposed on an AC wireless signal. The demodulation circuit is configured to receive the electrical information from the at least one sensor, apply automatic bias control and gain control to generate modified electrical information, detect a change in the modified electrical information and determine if the change in the modified electrical information meets or exceeds one of a rise threshold or a fall threshold. If the change exceeds one of the rise threshold or the fall threshold, an alert is generated. Alerts are decoded into the electrical information.

TECHNICAL FIELD

The present disclosure generally relates to systems and methods forwireless transfer of electrical power and/or electrical data signals,and, more particularly, to sensitive demodulation circuits for wirelesspower transfer systems to accurately demodulate in-band communicationssignals.

BACKGROUND

Wireless connection systems are used in a variety of applications forthe wireless transfer of electrical energy, electrical power,electromagnetic energy, electrical data signals, among other knownwirelessly transmittable signals. Such systems often use inductiveand/or resonant inductive wireless power transfer, which occurs whenmagnetic fields created by a transmitting element induce an electricfield and, hence, an electric current, in a receiving element. Thesetransmitting and receiving elements will often take the form of coiledwires and/or antennas.

Transmission of one or more of electrical energy, electrical power,electromagnetic energy and/or electronic data signals from one of suchcoiled antennas to another, generally, operates at an operatingfrequency and/or an operating frequency range. The operating frequencymay be selected for a variety of reasons, such as, but not limited to,power transfer characteristics, power level characteristics,self-resonant frequency restraints, design requirements, adherence tostandards bodies' required characteristics (e.g. electromagneticinterference (EMI) requirements, specific absorption rate (SAR)requirements, among other things), bill of materials (BOM), and/or formfactor constraints, among other things. It is to be noted that,“self-resonating frequency,” as known to those having skill in the art,generally refers to the resonant frequency of a passive component (e.g.,an inductor) due to the parasitic characteristics of the component.

When such systems operate to wirelessly transfer power from atransmission system to a receiver system via coils and/or antennas, itis often desired to simultaneously or intermittently communicateelectronic data from one system to the other. To that end, a variety ofcommunications systems, methods, and/or apparatus have been utilized forcombined wireless power and wireless data transfer. In some examplesystems, wireless power transfer related communications (e.g.,validation procedures, electronic characteristics data communications,voltage data, current data, device type data, among other contemplateddata communications) are performed using other circuitry, such asoptional Bluetooth chipsets and/or antennas for data communications,among other known communications circuits and/or antennas.

SUMMARY

However, using additional antennas and/or circuitry can give rise tonumerous disadvantages, and as such, in-band data transfer may bedesired. Nonetheless, such in-band transfer of data may itself becomeineffective or inefficient when the relative positions of the datasender and data receiver vary too greatly.

Sensitive demodulation circuits that allow for fast and accurate in-bandcommunications, regardless of the relative positions of the sender andreceiver within the power transfer range, are desired. The demodulationcircuit of the wireless power transmitters disclosed herein is a circuitthat is utilized to, at least in part, decode or demodulate ASK(amplitude shift keying) signals down to alerts for rising and fallingedges of a data signal. So long as the controller is programmed toproperly process the coding schema of the ASK modulation, thetransmission controller will expend less computational resources than itwould if it were required to decode the leading and falling edgesdirectly from an input current or voltage sense signal from the sensingsystem. To that end, the computational resources required by thetransmission controller to decode the wireless data signals aresignificantly decreased due to the inclusion of the demodulationcircuit.

This may in turn significantly reduce the BOM for the demodulationcircuit, and the wireless transmission system as a whole, by allowingusage of cheaper, less computationally capable processor(s) for or withthe transmission controller.

However, the throughput and accuracy of an edge-detection coding schemedepends in large part upon the system's ability to quickly andaccurately detect signal slope changes. Moreover, in environmentswherein the distance between, and orientations of, the sender andreceiver may change dynamically, the magnitude of the received powersignal and embedded data signal may also change dynamically. Thiscircumstance may cause a previously readable signal to become too faintto discern, or may cause a previously readable signal to becomesaturated.

In accordance with one aspect of the disclosure, a wireless transmissionsystem is disclosed. The wireless transmission system includes atransmitter antenna, at least one sensor, a demodulation circuit, and atransmitter controller. The transmitter antenna is configured to couplewith at least one other antenna of at least one other system andtransmit alternating current (AC) wireless signals to the at least oneother antenna, the AC wireless signals including wireless power signalsand wireless data signals, the wireless data signals generated byaltering electrical characteristics of the AC wireless signals at the atleast one other system. The at least one sensor is configured to detectelectrical information associated with the electrical characteristics ofthe AC wireless signals, the electrical information including one ormore of a current of the AC wireless signals, a voltage of the ACwireless signals and a power level of the AC wireless signals. Thedemodulation circuit is configured to (i) receive the electricalinformation from the at least one sensor, (ii) apply automatic biascontrol and gain control to the electrical information to generate amodified electrical information signal (iii) detect a change in themodified electrical information signal, (iv) determine if the change inthe modified electrical information signal meets or exceeds one of arise threshold or a fall threshold, (v) if the change exceeds one of therise threshold or the fall threshold, generate an alert, (v) and outputa plurality of data alerts. The transmitter controller is configured to(i) receive the plurality of data alerts from the demodulation circuit,and (ii) decode the plurality of data alerts into the wireless datasignals.

In a refinement, the demodulation circuit includes a slope detectioncircuit, and wherein the slope detection circuit comprises a first opamp(operational amplifier) for slope detection to produce a slope detectionsignal and a second opamp for amplification of the slope detectionsignal to generate an amplified slope detection signal.

In a further refinement, an offset voltage signal is supplied to thefirst opamp, the offset voltage signal being controlled by a firstdigital potentiometer within a first voltage divider, and wherein anamplification control signal is supplied to the second opamp, theamplification control signal being controlled by a second digitalpotentiometer within a second voltage divider.

In yet a further refinement, respective resistance values of the firstdigital potentiometer and the second digital potentiometer are set bythe transmitter controller.

In yet a further refinement, the transmitter controller sets therespective resistance values of the first digital potentiometer and thesecond digital potentiometer based on sensed current associated with thewireless data signals and sensed coupling strength between thetransmitter antenna and the at least one other antenna.

In a refinement, the electrical characteristics include a voltage of thewireless power signals, and wherein the demodulation circuit isconfigured to detect a change in the modified electrical informationsignal by determining a voltage rate of change of the voltage of themodified electrical information.

In a further refinement, the demodulation circuit includes a comparatorcircuit configured to (i) receive the voltage rate of change, (ii)compare the voltage rate of change to a rising rate of change, and (iii)determine that the change in the electrical characteristics meets orexceeds the rise threshold, if the voltage rate of change meets orexceeds the rising rate of change.

In another further refinement, the demodulation circuit includes acomparator circuit configured to (i) receive the voltage rate of change,(ii) compare the voltage rate of change to a falling rate of change, and(iii) determine that the change in the electrical characteristics meetsor exceeds the fall threshold, if the voltage rate of change meets orexceeds the falling rate of change.

In another further refinement, the demodulation circuit includes acomparator circuit configured to (i) receive the voltage rate of change,(ii) compare the voltage rate of change to a rising rate of change,(iii) determine that the change in the electrical characteristics meetsor exceeds the rise threshold, if the voltage rate of change meets orexceeds the rising rate of change, (iv) compare the voltage rate ofchange to a falling rate of change, and (v) determine that the change inthe electrical characteristics meets or exceeds the fall threshold, ifthe voltage rate of change meets or exceeds the falling rate of change.

In yet a further refinement, the demodulation circuit includes aset/reset (SR) latch in operative communication with an output of thecomparator circuit.

In a refinement, the transmission antenna is configured to operate basedon an operating frequency of about 6.78 MHz.

In accordance with another aspect of the disclosure, a demodulationcircuit for a wireless power transmission system is disclosed. Thedemodulation circuit includes a slope detector circuit and a comparatorcircuit. The slope detector circuit configured to determine a voltagerate of change for a voltage of the wireless power signals. Thecomparator circuit configured to (i) receive the voltage rate of change,(ii) apply automatic bias control and gain control to the voltage rateof change to generate a modified voltage rate of change (ii) compare themodified voltage rate of change to a rising rate of change, (iii)determine if the modified voltage rate of change meets or exceeds arising rate of change, (iv) compare the modified voltage rate of changeto a falling rate of change, (v) determine if the modified voltage rateof change of change meets or exceeds the falling rate of change and (vi)if the modified voltage rate of change exceeds the rising or fallingrate of change, generate an alert.

In accordance with yet another aspect of the disclosure, a method forconveying data in a wireless transmission system is disclosed. Themethod includes coupling a transmitter antenna with at least one otherantenna of at least one other system. The method further includestransmitting alternating current (AC) wireless signals from thetransmitter antenna to the at least one other antenna, the AC wirelesssignals including wireless power signals and wherein wireless datasignals are superimposed on the AC wireless signals by alteringelectrical characteristics of the AC wireless signals at the at leastone other system to generate modified AC wireless signals. The methodfurther includes detecting electrical information associated with theelectrical characteristics of the modified AC wireless signals, theelectrical information including one or more of a current of themodified AC wireless signals, a voltage of the modified AC wirelesssignals and a power level of the modified AC wireless signals. Themethod further includes receiving the electrical information, applyingautomatic bias control and gain control to the electrical information togenerate a modified electrical information signal, detecting a change inthe modified electrical information signal, determining if the change inthe modified electrical information signal meets or exceeds one of arise threshold or a fall threshold, generating a data alert if thechange exceeds one of the rise threshold or the fall threshold,outputting a plurality of data alerts, receiving the plurality of dataalerts, and decoding the plurality of data alerts into the wireless datasignals.

In a refinement, detecting a change in the modified electricalinformation signal comprise sensing an output of a slope detectioncircuit, the slope detection circuit having a first opamp (operationalamplifier) for slope detection to produce a slope detection signal and asecond opamp for amplification of the slope detection signal to generatean amplified slope detection signal.

In a further refinement, applying automatic bias control and gaincontrol to the electrical information to generate a modified electricalinformation signal comprises applying an offset voltage signal to thefirst opamp, the offset voltage signal being controlled by a firstdigital potentiometer within a first voltage divider, and applying anamplification control signal to the second opamp, the amplificationcontrol signal being controlled by a second digital potentiometer withina second voltage divider.

In yet a further refinement, setting the respective resistance values ofthe first digital potentiometer and the second digital potentiometer viathe transmitter controller based on sensed current associated with thewireless data signals and sensed coupling strength between thetransmitter antenna and the at least one other antenna.

In a refinement, detecting a change in the modified electricalinformation signal comprises determining a voltage rate of change of avoltage of the modified electrical information.

In a further refinement, determining if the change in the modifiedelectrical information signal meets or exceeds one of a rise thresholdor a fall threshold includes comparing the voltage rate of change to arising rate of change, determining that the change in the electricalcharacteristics meets or exceeds the rise threshold, if the voltage rateof change meets or exceeds the rising rate of change, comparing thevoltage rate of change to a falling rate of change, and determining thatthe change in the electrical characteristics meets or exceeds the fallthreshold, if the voltage rate of change meets or exceeds the fallingrate of change.

In a refinement, decoding the plurality of data alerts into the wirelessdata signals comprises passing the plurality of data alerts through atleast one set/reset (SR) latch.

In a refinement, transmitting AC wireless signals from the transmittercomprises transmitting at an operating frequency of about 6.78 MHz.

These and other aspects and features of the present disclosure will bebetter understood when read in conjunction with the accompanyingdrawings.

While the present disclosure is directed to a system that can eliminatecertain shortcomings noted in or apparent from this Background section,it should be appreciated that such a benefit is neither a limitation onthe scope of the disclosed principles nor of the attached claims, exceptto the extent expressly noted in the claims. Additionally, thediscussion of technology in this Background section is reflective of theinventors' own observations, considerations, and thoughts, and is in noway intended to accurately catalog or comprehensively summarize the artcurrently in the public domain. As such, the inventors expresslydisclaim this section as admitted or assumed prior art. Moreover, theidentification herein of a desirable course of action reflects theinventors' own observations and ideas, and should not be assumed toindicate an art-recognized desirability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an embodiment of a system for wirelesslytransferring one or more of electrical energy, electrical power signals,electrical power, electromagnetic energy, electronic data, andcombinations thereof, in accordance with the present disclosure.

FIG. 2 is a block diagram illustrating components of a wirelesstransmission system of FIG. 1 and a wireless receiver system of FIG. 1,in accordance with FIG. 1 and the present disclosure.

FIG. 3 is a block diagram illustrating components of a transmissioncontrol system of the wireless transmission system of FIG. 2, inaccordance with FIG. 1, FIG. 2, and the present disclosure.

FIG. 4 is a block diagram illustrating components of a sensing system ofthe transmission control system of FIG. 3, in accordance with FIGS. 1-3and the present disclosure.

FIG. 5 is a block diagram of an example low pass filter of the sensingsystem of FIG. 4, in accordance with FIGS. 1-4 and the presentdisclosure.

FIG. 6 is a block diagram illustrating components of a demodulationcircuit for the wireless transmission system of FIG. 2, in accordancewith FIGS. 1-5 and the present disclosure.

FIG. 7A is a first portion of a schematic circuit diagram for thedemodulation circuit of FIG. 6 in accordance with an embodiment of thepresent disclosure.

FIG. 7B is a second portion of the schematic circuit diagram for thedemodulation circuit of FIGS. 6 and 7A, in accordance with an embodimentof the present disclosure.

FIG. 8 is a timing diagram for voltages of an electrical signal, as ittravels through the demodulation circuit, in accordance with FIGS. 1-7and the present disclosure.

FIG. 9 is a block diagram illustrating components of a powerconditioning system of the wireless transmission system of FIG. 2, inaccordance with FIGS. 1-2, and the present disclosure.

FIG. 10 is a block diagram illustrating components of a receiver controlsystem and a receiver power conditioning system of the wireless receiversystem of FIG. 2, in accordance with FIGS. 1-2, and the presentdisclosure.

FIG. 11 is a top view of a non-limiting, exemplary antenna, for use as atransmitter or receiver antenna of the system of FIGS. 1-10 and/or anyother systems, methods, or apparatus disclosed herein, in accordancewith the present disclosure.

While the following detailed description will be given with respect tocertain illustrative embodiments, it should be understood that thedrawings are not necessarily to scale and the disclosed embodiments aresometimes illustrated diagrammatically and in partial views. Inaddition, in certain instances, details which are not necessary for anunderstanding of the disclosed subject matter or which render otherdetails too difficult to perceive may have been omitted. It shouldtherefore be understood that this disclosure is not limited to theparticular embodiments disclosed and illustrated herein, but rather to afair reading of the entire disclosure and claims, as well as anyequivalents thereto. Additional, different, or fewer components andmethods may be included in the systems and methods.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth byway of examples in order to provide a thorough understanding of therelevant teachings. However, it should be apparent to those skilled inthe art that the present teachings may be practiced without suchdetails. In other instances, well known methods, procedures, components,and/or circuitry have been described at a relatively high-level, withoutdetail, in order to avoid unnecessarily obscuring aspects of the presentteachings.

Referring now to the drawings and with specific reference to FIG. 1, awireless power transfer system 10 is illustrated. The wireless powertransfer system 10 provides for the wireless transmission of electricalsignals, such as, but not limited to, electrical energy, electricalpower, electrical power signals, electromagnetic energy, andelectronically transmittable data (“electronic data”). As used herein,the term “electrical power signal” refers to an electrical signaltransmitted specifically to provide meaningful electrical energy forcharging and/or directly powering a load, whereas the term “electronicdata signal” refers to an electrical signal that is utilized to conveydata across a medium.

The wireless power transfer system 10 provides for the wirelesstransmission of electrical signals via near field magnetic coupling. Asshown in the embodiment of FIG. 1, the wireless power transfer system 10includes one or more wireless transmission systems 20 and one or morewireless receiver systems 30. A wireless receiver system 30 isconfigured to receive electrical signals from, at least, a wirelesstransmission system 20.

As illustrated, the wireless transmission system(s) 20 and wirelessreceiver system(s) 30 may be configured to transmit electrical signalsacross, at least, a separation distance or gap 17. A separation distanceor gap, such as the gap 17, in the context of a wireless power transfersystem, such as the system 10, does not include a physical connection,such as a wired connection. There may be intermediary objects located ina separation distance or gap, such as, but not limited to, air, acounter top, a casing for an electronic device, a plastic filament, aninsulator, a mechanical wall, among other things; however, there is nophysical, electrical connection at such a separation distance or gap.

Thus, the combination of two or more wireless transmission systems 20and wireless receiver system 30 create an electrical connection withoutthe need for a physical connection. As used herein, the term “electricalconnection” refers to any facilitation of a transfer of an electricalcurrent, voltage, and/or power from a first location, device, component,and/or source to a second location, device, component, and/ordestination. An “electrical connection” may be a physical connection,such as, but not limited to, a wire, a trace, a via, among otherphysical electrical connections, connecting a first location, device,component, and/or source to a second location, device, component, and/ordestination. Additionally or alternatively, an “electrical connection”may be a wireless power and/or data transfer, such as, but not limitedto, magnetic, electromagnetic, resonant, and/or inductive field, amongother wireless power and/or data transfers, connecting a first location,device, component, and/or source to a second location, device,component, and/or destination.

Further, while FIGS. 1-2 may depict wireless power signals and wirelessdata signals transferring only from one antenna (e.g., a transmissionantenna 21) to another antenna (e.g., a receiver antenna 31 and/or atransmission antenna 21), it is certainly possible that a transmittingantenna 21 may transfer electrical signals and/or couple with one ormore other antennas and transfer, at least in part, components of theoutput signals or magnetic fields of the transmitting antenna 21. Suchtransmission may include secondary and/or stray coupling or signaltransfer to multiple antennas of the system 10.

In some cases, the gap 17 may also be referenced as a “Z-Distance,”because, if one considers antennas 21, 31 each to be disposedsubstantially along respective common X-Y planes, then the distanceseparating the antennas 21, 31 is the gap in a “Z” or “depth” direction.However, flexible and/or non-planar coils are certainly contemplated byembodiments of the present disclosure and, thus, it is contemplated thatthe gap 17 may not be uniform, across an envelope of connectiondistances between the antennas 21, 31. It is contemplated that varioustunings, configurations, and/or other parameters may alter the possiblemaximum distance of the gap 17, such that electrical transmission fromthe wireless transmission system 20 to the wireless receiver system 30remains possible. Moreover, in an embodiment, the characteristics of thegap 17 can change during use, such as by an increase or decrease indistance and/or a change in relative device orientations.

The wireless power transfer system 10 operates when the wirelesstransmission system 20 and the wireless receiver system 30 are coupled.As used herein, the terms “couples,” “coupled,” and “coupling” generallyrefer to magnetic field coupling, which occurs when a transmitter and/orany components thereof and a receiver and/or any components thereof arecoupled to each other through a magnetic field. Such coupling mayinclude coupling, represented by a coupling coefficient (k), that is atleast sufficient for an induced electrical power signal, from atransmitter, to be harnessed by a receiver. Coupling of the wirelesstransmission system 20 and the wireless receiver system 30, in thesystem 10, may be represented by a resonant coupling coefficient of thesystem 10 and, for the purposes of wireless power transfer, the couplingcoefficient for the system 10 may be in the range of about 0.01 and 0.9.

As illustrated, at least one wireless transmission system 20 isassociated with an input power source 12. The input power source 12 maybe operatively associated with a host device, which may be anyelectrically operated device, circuit board, electronic assembly,dedicated charging device, or any other contemplated electronic device.Example host devices, with which the wireless transmission system 20 maybe associated therewith, include, but are not limited to including, adevice that includes an integrated circuit, a portable computing device,storage medium for electronic devices, charging apparatus for one ormultiple electronic devices, dedicated electrical charging devices,among other contemplated electronic devices.

The input power source 12 may be or may include one or more electricalstorage devices, such as an electrochemical cell, a battery pack, and/ora capacitor, among other storage devices. Additionally or alternatively,the input power source 12 may be any electrical input source (e.g., anyalternating current (AC) or direct current (DC) delivery port) and mayinclude connection apparatus from said electrical input source to thewireless transmission system 20 (e.g., transformers, regulators,conductive conduits, traces, wires, or equipment, goods, computer,camera, mobile phone, and/or other electrical device connection portsand/or adaptors, such as but not limited to USB ports and/or adaptors,among other contemplated electrical components).

Electrical energy received by the wireless transmission system(s) 20 isthen used for at least two purposes: to provide electrical power tointernal components of the wireless transmission system 20 and toprovide electrical power to the transmission antenna 21. Thetransmission antenna 21 is configured to wirelessly transmit theelectrical signals conditioned and modified for wireless transmission bythe wireless transmission system 20 via near-field magnetic coupling(NFMC). Near-field magnetic coupling enables the transfer of signalswirelessly through magnetic induction between the transmission antenna21 and one or more of receiving antenna 31 of, or associated with, thewireless receiver system 30, another transmission antenna 21, orcombinations thereof. Near-field magnetic coupling may be and/or bereferred to as “inductive coupling,” which, as used herein, is awireless power transmission technique that utilizes an alternatingelectromagnetic field to transfer electrical energy between twoantennas. Such inductive coupling is the near field wirelesstransmission of magnetic energy between two magnetically coupled coilsthat are tuned to resonate at a similar frequency. Accordingly, suchnear-field magnetic coupling may enable efficient wireless powertransmission via resonant transmission of confined magnetic fields.Further, such near-field magnetic coupling may provide connection via“mutual inductance,” which, as defined herein is the production of anelectromotive force in a circuit by a change in current in a secondcircuit magnetically coupled to the first.

In one or more embodiments, the inductor coils of either thetransmission antenna 21 or the receiver antenna 31 are strategicallypositioned to facilitate reception and/or transmission of wirelesslytransferred electrical signals through near field magnetic induction.Antenna operating frequencies may comprise relatively high operatingfrequency ranges, examples of which may include, but are not limited to,6.78 MHz (e.g., in accordance with the Rezence and/or Airfuel interfacestandard and/or any other proprietary interface standard operating at afrequency of 6.78 MHz), 13.56 MHz (e.g., in accordance with the NFCstandard, defined by ISO/IEC standard 18092), 27 MHz, and/or anoperating frequency of another proprietary operating mode. The operatingfrequencies of the antennas 21, 31 may be operating frequenciesdesignated by the International Telecommunications Union (ITU) in theIndustrial, Scientific, and Medical (ISM) frequency bands, including notlimited to 6.78 MHz, 13.56 MHz, and 27 MHz, which are designated for usein wireless power transfer.

The transmitting antenna and the receiving antenna of the presentdisclosure may be configured to transmit and/or receive electrical powerhaving a magnitude that ranges from about 10 milliwatts (mW) to about500 watts (W). In one or more embodiments the inductor coil of thetransmitting antenna 21 is configured to resonate at a transmittingantenna resonant frequency or within a transmitting antenna resonantfrequency band.

As known to those skilled in the art, a “resonant frequency” or“resonant frequency band” refers a frequency or frequencies whereinamplitude response of the antenna is at a relative maximum, or,additionally or alternatively, the frequency or frequency band where thecapacitive reactance has a magnitude substantially similar to themagnitude of the inductive reactance. In one or more embodiments, thetransmitting antenna resonant frequency is at a high frequency, as knownto those in the art of wireless power transfer.

The wireless receiver system 30 may be associated with at least oneelectronic device 14, wherein the electronic device 14 may be any devicethat requires electrical power for any function and/or for power storage(e.g., via a battery and/or capacitor). Additionally, the electronicdevice 14 may be any device capable of receipt of electronicallytransmissible data. For example, the device may be, but is not limitedto being, a handheld computing device, a mobile device, a portableappliance, a computer peripheral, an integrated circuit, an identifiabletag, a kitchen utility device, an electronic tool, an electric vehicle,a game console, a robotic device, a wearable electronic device (e.g., anelectronic watch, electronically modified glasses, altered-reality (AR)glasses, virtual reality (VR) glasses, among other things), a portablescanning device, a portable identifying device, a sporting good, anembedded sensor, an Internet of Things (IoT) sensor, IoT enabledclothing, IoT enabled recreational equipment, industrial equipment,medical equipment, a medical device a tablet computing device, aportable control device, a remote controller for an electronic device, agaming controller, among other things.

For the purposes of illustrating the features and characteristics of thedisclosed embodiments, arrow-ended lines are utilized to illustratetransferrable and/or communicative signals and various patterns are usedto illustrate electrical signals that are intended for powertransmission and electrical signals that are intended for thetransmission of data and/or control instructions. Solid lines indicatesignal transmission of electrical energy over a physical and/or wirelesspower transfer, in the form of power signals that are, ultimately,utilized in wireless power transmission from the wireless transmissionsystem 20 to the wireless receiver system 30. Further, dotted lines areutilized to illustrate electronically transmittable data signals, whichultimately may be wirelessly transmitted from the wireless transmissionsystem 20 to the wireless receiver system 30.

While the systems and methods herein illustrate the transmission ofwirelessly transmitted energy, wireless power signals, wirelesslytransmitted power, wirelessly transmitted electromagnetic energy, and/orelectronically transmittable data, it is certainly contemplated that thesystems, methods, and apparatus disclosed herein may be utilized in thetransmission of only one signal, various combinations of two signals, ormore than two signals and, further, it is contemplated that the systems,method, and apparatus disclosed herein may be utilized for wirelesstransmission of other electrical signals in addition to or uniquely incombination with one or more of the above mentioned signals. In someexamples, the signal paths of solid or dotted lines may represent afunctional signal path, whereas, in practical application, the actualsignal is routed through additional components en route to its indicateddestination. For example, it may be indicated that a data signal routesfrom a communications apparatus to another communications apparatus;however, in practical application, the data signal may be routed throughan amplifier, then through a transmission antenna, to a receiverantenna, where, on the receiver end, the data signal is decoded by arespective communications device of the receiver.

Turning now to FIGS. 2-3, the wireless power transfer system 10 isillustrated as a block diagram including example sub-systems of both thewireless transmission systems 20 and the wireless receiver systems 30.The wireless transmission systems 20 may include, at least, a powerconditioning system 40, a transmission control system 26, a demodulationcircuit 70, a transmission tuning system 24, and the transmissionantenna 21. A first portion of the electrical energy input from theinput power source 12 may be configured to electrically power componentsof the wireless transmission system 20 such as, but not limited to, thetransmission control system 26.

A second portion of the electrical energy input from the input powersource 12 is conditioned and/or modified for wireless powertransmission, to the wireless receiver system 30, via the transmissionantenna 21. Accordingly, the second portion of the input energy ismodified and/or conditioned by the power conditioning system 40. Whilenot illustrated, it is certainly contemplated that one or both of thefirst and second portions of the input electrical energy may bemodified, conditioned, altered, and/or otherwise changed prior toreceipt by the power conditioning system 40 and/or transmission controlsystem 26, by further contemplated subsystems (e.g., a voltageregulator, a current regulator, switching systems, fault systems, safetyregulators, among other things).

Referring more specifically now to FIG. 3, with continued reference toFIGS. 1 and 2, subcomponents and/or systems of the transmission controlsystem 26 are illustrated. The transmission control system 26 mayinclude a sensing system 50, a transmission controller 28, a driver 48,a memory 27 and a demodulation circuit 70.

The transmission controller 28 may be any electronic controller orcomputing system that includes, at least, a processor which performsoperations, executes control algorithms, stores data, retrieves data,gathers data, controls and/or provides communication with othercomponents and/or subsystems associated with the wireless transmissionsystem 20, and/or performs any other computing or controlling taskdesired. The transmission controller 28 may be a single controller ormay include more than one controller disposed to control variousfunctions and/or features of the wireless transmission system 20.Functionality of the transmission controller 28 may be implemented inhardware and/or software and may rely on one or more data maps relatingto the operation of the wireless transmission system 20. To that end,the transmission controller 28 may be operatively associated with thememory 27.

The memory may include one or more of internal memory, external memory,and/or remote memory (e.g., a database and/or server operativelyconnected to the transmission controller 28 via a network, such as, butnot limited to, the Internet). The internal memory and/or externalmemory may include, but are not limited to including, one or more of aread only memory (ROM), including programmable read-only memory (PROM),erasable programmable read-only memory (EPROM or sometimes but rarelylabelled EROM), electrically erasable programmable read-only memory(EEPROM), random access memory (RAM), including dynamic RAM (DRAM),static RAM (SRAM), synchronous dynamic RAM (SDRAM), single data ratesynchronous dynamic RAM (SDR SDRAM), double data rate synchronousdynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4), and graphics double data ratesynchronous dynamic RAM (GDDR SDRAM, GDDR2, GDDR3, GDDR4, GDDR5, a flashmemory, a portable memory, and the like. Such memory media are examplesof nontransitory machine readable and/or computer readable memory media.

While particular elements of the transmission control system 26 areillustrated as independent components and/or circuits (e.g., the driver48, the memory 27, the sensing system 50, among other contemplatedelements) of the transmission control system 26, such components may beintegrated with the transmission controller 28. In some examples, thetransmission controller 28 may be an integrated circuit configured toinclude functional elements of one or both of the transmissioncontroller 28 and the wireless transmission system 20, generally.

As illustrated, the transmission controller 28 is in operativeassociation, for the purposes of data transmission, receipt, and/orcommunication, with, at least, the memory 27, the power conditioningsystem 40, the driver 48, and the sensing system 50. The driver 48 maybe implemented to control, at least in part, the operation of the powerconditioning system 40. In some examples, the driver 48 may receiveinstructions from the transmission controller 28 to generate and/oroutput a generated pulse width modulation (PWM) signal to the powerconditioning system 40. In some such examples, the PWM signal may beconfigured to drive the power conditioning system 40 to outputelectrical power as an alternating current signal, having an operatingfrequency defined by the PWM signal. In some examples, PWM signal may beconfigured to generate a duty cycle for the AC power signal output bythe power conditioning system 40. In some such examples, the duty cyclemay be configured to be about 50% of a given period of the AC powersignal.

The sensing system may include one or more sensors, wherein each sensormay be operatively associated with one or more components of thewireless transmission system 20 and configured to provide informationand/or data. The term “sensor” is used in its broadest interpretation todefine one or more components operatively associated with the wirelesstransmission system 20 that operate to sense functions, conditions,electrical characteristics, operations, and/or operating characteristicsof one or more of the wireless transmission system 20, the wirelessreceiving system 30, the input power source 12, the host device 11, thetransmission antenna 21, the receiver antenna 31, along with any othercomponents and/or subcomponents thereof.

As illustrated in the embodiment of FIG. 4, the sensing system 50 mayinclude, but is not limited to including, a thermal sensing system 52,an object sensing system 54, a receiver sensing system 56, a currentsensor 57, and/or any other sensor(s) 58. Within these systems, theremay exist even more specific optional additional or alternative sensingsystems addressing particular sensing aspects required by anapplication, such as, but not limited to: a condition-based maintenancesensing system, a performance optimization sensing system, astate-of-charge sensing system, a temperature management sensing system,a component heating sensing system, an IoT sensing system, an energyand/or power management sensing system, an impact detection sensingsystem, an electrical status sensing system, a speed detection sensingsystem, a device health sensing system, among others. The object sensingsystem 54, may be a foreign object detection (FOD) system.

Each of the thermal sensing system 52, the object sensing system 54, thereceiver sensing system 56, the current sensor 57 and/or the othersensor(s) 58, including the optional additional or alternative systems,are operatively and/or communicatively connected to the transmissioncontroller 28. The thermal sensing system 52 is configured to monitorambient and/or component temperatures within the wireless transmissionsystem 20 or other elements nearby the wireless transmission system 20.The thermal sensing system 52 may be configured to detect a temperaturewithin the wireless transmission system 20 and, if the detectedtemperature exceeds a threshold temperature, the transmission controller28 prevents the wireless transmission system 20 from operating. Such athreshold temperature may be configured for safety considerations,operational considerations, efficiency considerations, and/or anycombinations thereof. In a non-limiting example, if, via input from thethermal sensing system 52, the transmission controller 28 determinesthat the temperature within the wireless transmission system 20 hasincreased from an acceptable operating temperature to an undesiredoperating temperature (e.g., in a non-limiting example, the internaltemperature increasing from about 20° Celsius (C) to about 50° C., thetransmission controller 28 prevents the operation of the wirelesstransmission system 20 and/or reduces levels of power output from thewireless transmission system 20. In some non-limiting examples, thethermal sensing system 52 may include one or more of a thermocouple, athermistor, a negative temperature coefficient (NTC) resistor, aresistance temperature detector (RTD), and/or any combinations thereof.

As depicted in FIG. 4, the transmission sensing system 50 may includethe object sensing system 54. The object sensing system 54 may beconfigured to detect one or more of the wireless receiver system 30and/or the receiver antenna 31, thus indicating to the transmissioncontroller 28 that the receiver system 30 is proximate to the wirelesstransmission system 20. Additionally or alternatively, the objectsensing system 54 may be configured to detect presence of unwantedobjects in contact with or proximate to the wireless transmission system20. In some examples, the object sensing system 54 is configured todetect the presence of an undesired object. In some such examples, ifthe transmission controller 28, via information provided by the objectsensing system 54, detects the presence of an undesired object, then thetransmission controller 28 prevents or otherwise modifies operation ofthe wireless transmission system 20. In some examples, the objectsensing system 54 utilizes an impedance change detection scheme, inwhich the transmission controller 28 analyzes a change in electricalimpedance observed by the transmission antenna 20 against a known,acceptable electrical impedance value or range of electrical impedancevalues.

Additionally or alternatively, the object sensing system 54 may utilizea quality factor (Q) change detection scheme, in which the transmissioncontroller 28 analyzes a change from a known quality factor value orrange of quality factor values of the object being detected, such as thereceiver antenna 31. The “quality factor” or “Q” of an inductor can bedefined as (frequency (Hz)×inductance (H))/resistance (ohms), wherefrequency is the operational frequency of the circuit, inductance is theinductance output of the inductor and resistance is the combination ofthe radiative and reactive resistances that are internal to theinductor. “Quality factor,” as defined herein, is generally accepted asan index (figure of measure) that measures the efficiency of anapparatus like an antenna, a circuit, or a resonator. In some examples,the object sensing system 54 may include one or more of an opticalsensor, an electro-optical sensor, a Hall Effect sensor, a proximitysensor, and/or any combinations thereof. In some examples, the qualityfactor measurements, described above, may be performed when the wirelesspower transfer system 10 is performing in band communications.

The receiver sensing system 56 is any sensor, circuit, and/orcombinations thereof configured to detect a presence of any wirelessreceiving system that may be couplable with the wireless transmissionsystem 20. In some examples, the receiver sensing system 56 and theobject sensing system 54 may be combined, may share components, and/ormay be embodied by one or more common components. In some examples, ifthe presence of any such wireless receiving system is detected, wirelesstransmission of electrical energy, electrical power, electromagneticenergy, and/or data by the wireless transmission system 20 to saidwireless receiving system is enabled. In some examples, if the presenceof a wireless receiver system is not detected, continued wirelesstransmission of electrical energy, electrical power, electromagneticenergy, and/or data is prevented from occurring. Accordingly, thereceiver sensing system 56 may include one or more sensors and/or may beoperatively associated with one or more sensors that are configured toanalyze electrical characteristics within an environment of or proximateto the wireless transmission system 20 and, based on the electricalcharacteristics, determine presence of a wireless receiver system 30.

The current sensor 57 may be any sensor configured to determineelectrical information from an electrical signal, such as a voltage or acurrent, based on a current reading at the current sensor 57. Componentsof an example current sensor 57 are further illustrated in FIG. 5, whichis a block diagram for the current sensor 57. The current sensor 57 mayinclude a transformer 51, a rectifier 53, and/or a low pass filter 55,to process the AC wireless signals, transferred via coupling between thewireless receiver system(s) 20 and wireless transmission system(s) 30,to determine or provide information to derive a current (I_(Tx)) orvoltage (V_(Tx)) at the transmission antenna 21. The transformer 51 mayreceive the AC wireless signals and either step up or step down thevoltage of the AC wireless signal, such that it can properly beprocessed by the current sensor. The rectifier 53 may receive thetransformed AC wireless signal and rectify the signal, such that anynegative voltages remaining in the transformed AC wireless signal areeither eliminated or converted to opposite positive voltages, togenerate a rectified AC wireless signal. The low pass filter 55 isconfigured to receive the rectified AC wireless signal and filter out ACcomponents (e.g., the operating or carrier frequency of the AC wirelesssignal) of the rectified AC wireless signal, such that a DC voltage isoutput for the current (I_(Tx)) and/or voltage (V_(Tx)) at thetransmission antenna 21.

FIG. 6 is a block diagram for a demodulation circuit 70 for the wirelesstransmission system(s) 20, which is used by the wireless transmissionsystem 20 to simplify or decode components of wireless data signals ofan alternating current (AC) wireless signal, prior to transmission ofthe wireless data signal to the transmission controller 28. Thedemodulation circuit includes, at least, a slope detector 72 and acomparator 74. In some examples, the demodulation circuit 70 includes aset/reset (SR) latch 76.

In some examples, the demodulation circuit 70 may be an analog circuitcomprised of one or more passive components (e.g., resistors,capacitors, inductors, diodes, among other passive components) and/orone or more active components (e.g., operational amplifiers, logicgates, among other active components). Alternatively, it is contemplatedthat the demodulation circuit 70 and some or all of its components maybe implemented as an integrated circuit (IC). In either an analogcircuit or IC, it is contemplated that the demodulation circuit may beexternal of the transmission controller 28 and is configured to provideinformation associated with wireless data signals transmitted from thewireless receiver system 30 to the wireless transmission system 20.

The demodulation circuit 70 is configured to receive electricalinformation (e.g., I_(Tx), V_(Tx)) from at least one sensor (e.g., asensor of the sensing system 50), detect a change in such electricalinformation, determine if the change in the electrical information meetsor exceeds one of a rise threshold or a fall threshold. If the changeexceeds one of the rise threshold or the fall threshold, thedemodulation circuit 70 generates an output signal and also generatesand outputs one or more data alerts. Such data alerts are received bythe transmitter controller 28 and decoded by the transmitter controller28 to determine the wireless data signals.

In other words, in an embodiment, the demodulation circuit 70 isconfigured to monitor the slope of an electrical signal (e.g., slope ofa voltage signal at the power conditioning system 32 of a wirelessreceiver system 30) and to output an indication when said slope exceedsa maximum slope threshold or undershoots a minimum slope threshold. Suchslope monitoring and/or slope detection by the communications system 70is particularly useful when detecting or decoding an amplitude shiftkeying (ASK) signal that encodes the wireless data signals in-band ofthe wireless power signal (which is oscillating at the operatingfrequency).

In an ASK signal, as noted above, the wireless data signals are encodedby damping the voltage of the magnetic field between the wirelesstransmission system 20 and the wireless receiver system 30. Such dampingand subsequent re-rising of the voltage in the field is performed basedon an underlying encoding scheme for the wireless data signals (e.g.,binary coding, Manchester coding, pulse-width modulated coding, amongother known or novel coding systems and methods). The receiver of thewireless data signals (e.g., the wireless transmission system 20 in thisexample) can then detect rising and falling edges of the voltage of thefield and decode said rising and falling edges to demodulate thewireless data signals.

Ideally, an ASK signal would rise and fall instantaneously, with nodiscernable slope between the high voltage and the low voltage for ASKmodulation; however, in reality, there is a finite amount of time thatpasses when the ASK signal transitions from the “high” voltage to the“low” voltage and vice versa. Thus, the voltage or current signal to besensed by the demodulation circuit 70 will have some slope or rate ofchange in voltage when transitioning. By configuring the demodulationcircuit 70 to determine when said slope meets, overshoots and/orundershoots such rise and fall thresholds, established based on theknown maximum/minimum slope of the carrier signal at the operatingfrequency, the demodulation circuit can accurately detect rising andfalling edges of the ASK signal.

Thus, a relatively inexpensive and/or simplified circuit may be utilizedto at least partially decode ASK signals down to notifications or alertsfor rising and falling slope instances. As long as the transmissioncontroller 28 is programmed to understand the coding schema of the ASKmodulation, the transmission controller 28 will expend far lesscomputational resources than would have been needed to decode theleading and falling edges directly from an input current or voltagesense signal from the sensing system 50. To that end, as thecomputational resources required by the transmission controller 28 todecode the wireless data signals are significantly decreased due to theinclusion of the demodulation circuit 70, the demodulation circuit 70may significantly reduce BOM of the wireless transmission system 20, byallowing usage of cheaper, less computationally capable processor(s) foror with the transmission controller 28.

The demodulation circuit 70 may be particularly useful in reducing thecomputational burden for decoding data signals, at the transmittercontroller 28, when the ASK wireless data signals are encoded/decodedutilizing a pulse-width encoded ASK signals, in-band of the wirelesspower signals. A pulse-width encoded ASK signal is a signal wherein thedata is encoded as a percentage of a period of a signal. For example, atwo-bit pulse width encoded signal may encode a start bit as 20% of aperiod between high edges of the signal, encode “1” as 40% of a periodbetween high edges of the signal, and encode “0” as 60% of a periodbetween high edges of the signal, to generate a binary encoding formatin the pulse width encoding scheme.

Thus, as the pulse width encoding relies solely on monitoring rising andfalling edges of the ASK signal, the periods between rising times neednot be constant and the data signals may be asynchronous or “unclocked.”Examples of pulse width encoding and systems and methods to perform suchpulse width encoding are explained in greater detail in U.S. patentapplication Ser. No. 16/735,342 titled “Systems and Methods for WirelessPower Transfer Including Pulse Width Encoded Data Communications,” toMichael Katz, which is commonly owned by the owner of the instantapplication and is hereby incorporated by reference in its entirety, forall that it teaches without exclusion of any part thereof.

As noted above, slope detection, and hence in-band transfer of data, maybecome ineffective or inefficient when the signal strength varies fromthe parameters relied upon during design. For example, when the relativepositions of the data sender and data receiver vary significantly duringuse of the system, the electromagnetic coupling between sender andreceiver coils or antennas will also vary. Data detection and decodingare optimized for a particular coupling may fail or underperform atother couplings. As such, a high sensitivity non-saturating detectionsystem is needed to allow the system to operate in environments whereincoupling changes dynamically.

For example, referring to FIG. 7, the signal created by the high passfilter 71 of the slope detector 72, prior to being amplified by OP_(SD),will vary as a result of varying coupling (as will the power signal,but, for the purposes of the discussion of in-band data, it has now beenfiltered out at this point). Thus, the difference in magnitude of theamplified signals will vary by even more. At the upper end,substantially improved coupling may cause saturation of OP_(SD), at saidupper end, if the system is tuned for small signal detection. Similarly,substantially degraded coupling may result in an undetectable signal ifthe system is tuned for high, good, and/or fair coupling. Moreover, apre-amp signal with a positive offset may result in clipped (e.g.,saturated) positive signals, post-amplification, unless gain is reduced;however, the reduced gain may in turn render negative signalsundetectable. Additionally, a varying load at the receiver may affectthe signal, necessitating the amplification of the data signal at theslope detector 72.

As such, instability in coupling is generally not well-tolerated byinductive charging systems, since it causes the filtered and amplifiedsignal to vary too greatly. For example, a phone placed into a fitteddock will stay in a specific location relative to the dock, and anycoupling therebetween will remain relatively constant. However, a phoneplaced on a desktop with an inductive charging station under the desktopmay not maintain a fixed relative location, nor a fixed relativeorientation and, thus, the range of coupling between the transmitter andthe receiver of the phone may vary during the charging process. Further,consider a wireless power system configured for directly powering and/orcharging a medical device, while the medical device resides within ahuman body. Due to natural displacement and/or internal movement oforganic elements of the human body, the medical device may not maintainconstant location, relative to the body and/or an associated chargerpositioned outside of the body, and, thus, the transmitter and receivermay couple at a wide range of high, good, fair, low, and/or insufficientcoupling levels. Further still, consider a computer peripheral beingcharged by a charging mat on a user's desk. It may be desired to chargesaid peripheral, such as a mouse or other input device, during use ofthe device; such use of the peripheral will necessarily alter couplingduring use, as it will be moved regularly, with respect to positioningof the transmitting charging mat.

The effect caused by a difference in the coupling coefficient k can beillustrated by a few non-limiting examples. Consider a case whereink=0.041, representing fairly strong coupling. In this case, the inducedvoltage delta (V_(delta)) may be about 160 mV, with the correspondingamplified signal running between a peak of 3.15V and a nadir of 0.45V,for a swing of about 2.70V around a DC offset of 1.86V (i.e., 1.35Vabove and below the DC offset value).

Now consider a case in the same system wherein a coupling value of 0.01is exhibited, representing fairly weak coupling. This weakening couldhappen due to relative movement, intervening materials, or othercircumstance. Now V_(delta) may be about 15 mV, with the correspondingamplified signal running between a peak of 1.94V and a nadir of 1.77V,for a swing of about 140 mV around a DC offset of 1.86V (i.e., about 70mV above and below the DC offset value).

As can be seen from this example, while the strongly coupled case yieldsrobust signals, the weakly coupled case yields very small signals atop afairly large offset. While perhaps generally detectable, these signallevel present a significant risk of data errors and consequently loweredthroughput. Moreover, while there is room for increased amplification,the level of amplification, especially given the DC offset, isconstrained by the saturation level of the available economicaloperational amplifier circuits, which, in some examples may be about4.0V.

However, in an embodiment, automatic gain control in amplification iscombined with a voltage offset in slope detection to allow the system toadapt to varying degrees of coupling. This is especially helpful insituations where the physical locations of the coupled devices are nottightly constrained during coupling.

Continuing with the example of FIG. 7, in the illustrated circuit 72,the bias voltage V′_(Bias) for slope detection is provided by a voltagedivider 77 (including linked resistors R_(B1), R_(B2), R_(B3)), whichprovides a voltage between V_(in) and ground based on a control voltageV_(HB). Given the control voltage V_(HB), the bias voltage V′Bias is setby adjusting a resistance in the voltage divider. In this connection,one of the resistors, e.g., R_(B3), may be a variable resistor, such asa digitally adjustable potentiometer, with the specific resistance beinggenerated via an adaptive bias and gain protocol to be described below,e.g., R_(bias).

Similarly, in the illustrated circuit 72, the output voltage V_(SD)provided to the next stage, comparator 74, is first amplified at a levelset by a voltage divider 80 (including linked resistors R_(A1), R_(A2),R_(A3)), based on the control voltage V_(HA) to generate V′_(SD) (slopedetection signal). The amplification of V_(SD) to generate V′_(SD)(amplified slope detection signal) is similarly set via a variablepotentiometer in the voltage divider, e.g., R_(A1), being set to aspecific value, e.g., R_(gain) generated via an adaptive bias and gainprotocol to be described later below.

With respect to the aforementioned, non-limiting example, with automaticgain and bias in slope detection, the circuit is configured toaccommodate a V_(amp slope delta) of between 400 mv and 2.2V, and aV_(amp DC) offset of between 1.8V and 2.2V. In order to determineappropriate offsets and gains, the system may employ a beaconingsequence state. The beaconing sequence ensures that the transmitter isgenerally able to detect the receiver at all possible allowed couplingpositions and orientations.

Referring still to FIG. 7, the slope detector 72 includes a high passfilter 71 and an optional stabilizing circuit 73. The high pass filter71 is configured to monitor for higher frequency components of the ACwireless signals and may include, at least, a filter capacitor (C_(HF))and a filter resistor (R_(HF)). The values for C_(HF) and R_(HF) areselected and/or tuned for a desired cutoff frequency for the high passfilter 71. In some examples, the cutoff frequency for the high passfilter 71 may be selected as a value greater than or equal to about 1-2kHz, to ensure adequately fast slope detection by the slope detector 72,when the operating frequency of the system 10 is on the order of MHz(e.g., an operating frequency of about 6.78 MHz). In some examples, thehigh pass filter 71 is configured such that harmonic components of thedetected slope are unfiltered. In view of the current sensor 57 of FIG.5, the high pass filter 71 and the low pass filter 55, in combination,may function as a bandpass filter for the demodulation circuit 70.

OP_(SD) is any operational amplifier having an adequate bandwidth forproper signal response, for outputting the slope of V_(Tx), but lowenough to attenuate components of the signal that are based on theoperating frequency and/or harmonics of the operating frequency.Additionally or alternatively, OP_(SD) may be selected to have a smallinput voltage range for V_(Tx), such that OP_(SD) may avoid unnecessaryerror or clipping during large changes in voltage at V_(Tx). Further, aninput bias voltage (V_(Bias)) for OP_(SD) may be selected based onvalues that ensure OP_(SD) will not saturate under boundary conditions(e.g., steepest slopes, largest changes in V_(Tx)). It is to be noted,and is illustrated in Plot B of FIG. 8, that when no slope is detected,the output of the slope detector 72 will be V_(Bias).

As the passive components of the slope detector 72 will set theterminals and zeroes for a transfer function of the slope detector 72,such passive components must be selected to ensure stability. To thatend, if the desired and/or available components selected for C_(HF) andR_(HF) do not adequately set the terminals and zeros for the transferfunction, additional, optional stability capacitor(s) C_(ST) may beplaced in parallel with R_(HF) and stability resistor R_(ST) may beplaced in the input path to OP_(SD).

Output of the slope detector 72 (Plot B representing V_(SD)) mayapproximate the following equation:

$V_{SD} = {{{- R_{HF}}C_{HF}\frac{dV}{dt}} + V_{Bias}}$

Thus, V_(SD) will approximate to V_(Bias), when no change in voltage(slope) is detected, and Output V_(SD) of the slope detector 72 isrepresented in Plot B. As can be seen, the value of V_(SD) approximatesV_(Bias) when no change in voltage (slope) is detected, whereas V_(SD)will output the change in voltage (dV/dt), as scaled by the high passfilter 71, when V_(Tx) rises and falls between the high voltage and thelow voltage of the ASK modulation. The output of the slope detector 72,as illustrated in Plot B, may be a pulse, showing slope of V_(Tx) riseand fall.

V_(SD) is output to the comparator circuit(s) 74, which is configured toreceive V_(SD), compare V_(SD) to a rising rate of change for thevoltage (V_(SUp)) and a falling rate of change for the voltage(V_(SLo)). If V_(SD) exceeds or meets V_(SUp), then the comparatorcircuit will determine that the change in V_(Tx) meets the risethreshold and indicates a rising edge in the ASK modulation. If V_(SD)goes below or meets V_(SLow), then the comparator circuit will determinethat the change in V_(Tx) meets the fall threshold and indicates afalling edge of the ASK modulation. It is to be noted that V_(SUp) andV_(SLo) may be selected to ensure a symmetrical triggering.

FIG. 8 is an exemplary timing diagram illustrating signal shape orwaveform at various stages or sub-circuits of the demodulation circuit70. The input signal to the demodulation circuit 70 is illustrated inFIG. 8 as Plot A, showing rising and falling edges from a “high” voltage(V_(High)) perturbation on the transmission antenna 21 to a “low”voltage (V_(Low)) perturbation on the transmission antenna 21. Thevoltage signal of Plot A may be derived from, for example, a current(I_(TX)) sensed at the transmission antenna 21 by one or more sensors ofthe sensing system 50. Such rises and falls from V_(High) to V_(Low) maybe caused by load modulation, performed at the wireless receiversystem(s) 30, to modulate the wireless power signals to include thewireless data signals via ASK modulation. As illustrated, the voltage ofPlot A does not cleanly rise and fall when the ASK modulation isperformed; rather, a slope or slopes, indicating rate(s) of change,occur during the transitions from V_(High) to V_(Low) and vice versa.

As illustrated in FIG. 7, the slope detector 72 includes a high passfilter 71, an operation amplifier (OpAmp) OP_(SD), and an optionalstabilizing circuit 73. The high pass filter 71 is configured to monitorfor higher frequency components of the AC wireless signals and mayinclude, at least, a filter capacitor (C_(HF)) and a filter resistor(R_(HF)). The values for C_(HF) and R_(HF) are selected and/or tuned fora desired cutoff frequency for the high pass filter 71. In someexamples, the cutoff frequency for the high pass filter 71 may beselected as a value greater than or equal to about 1-2 kHz, to ensureadequately fast slope detection by the slope detector 72, when theoperating frequency of the system 10 is on the order of MHz (e.g., anoperating frequency of about 6.78 MHz). In some examples, the high passfilter 71 is configured such that harmonic components of the detectedslope are unfiltered. In view of the current sensor 57 of FIG. 5, thehigh pass filter 71 and the low pass filter 55, in combination, mayfunction as a bandpass filter for the demodulation circuit 70.

OP_(SD) is any operational amplifier having an adequate bandwidth forproper signal response, for outputting the slope of V_(Tx), but lowenough to attenuate components of the signal that are based on theoperating frequency and/or harmonics of the operating frequency.Additionally or alternatively, OP_(SD) may be selected to have a smallinput voltage range for V_(Tx), such that OP_(SD) may avoid unnecessaryerror or clipping during large changes in voltage at V_(Tx). Further, aninput bias voltage (V_(Bias)) for OP_(SD) may be selected based onvalues that ensure OP_(SD) will not saturate under boundary conditions(e.g., steepest slopes, largest changes in V_(Tx)). It is to be noted,and is illustrated in Plot B of FIG. 8, that when no slope is detected,the output of the slope detector 72 will be V_(Bias).

As the passive components of the slope detector 72 will set theterminals and zeroes for a transfer function of the slope detector 72,such passive components must be selected to ensure stability. To thatend, if the desired and/or available components selected for C_(HF) andR_(HF) do not adequately set the terminals and zeros for the transferfunction, additional, optional stability capacitor(s) C_(ST) may beplaced in parallel with R_(HF) and stability resistor R_(ST) may beplaced in the input path to OP_(SD).

Output of the slope detector 72 (Plot B representing V_(SD)) mayapproximate the following equation:

$V_{SD} = {{{- R_{HF}}C_{HF}\frac{dV}{dt}} + V_{Bias}}$

Thus, V_(SD) will approximate to V_(Bias), when no change in voltage(slope) is detected, and output V_(SD) of the slope detector 72 isrepresented in Plot B. As can be seen, the value of V_(SD) approximatesV_(Bias) when no change in voltage (slope) is detected, whereas V_(SD)will output the change in voltage (dV/dt), as scaled by the high passfilter 71, when V_(Tx) rises and falls between the high voltage and thelow voltage of the ASK modulation. The output of the slope detector 72,as illustrated in Plot B, may be a pulse, showing slope of V_(Tx) riseand fall.

V_(SD) is output to the comparator circuit(s) 74, which is configured toreceive V_(SD), compare V_(SD) to a rising rate of change for thevoltage (V_(SUp)) and a falling rate of change for the voltage(V_(SLo)). If V_(SD) exceeds or meets V_(SUp), then the comparatorcircuit will determine that the change in V_(Tx) meets the risethreshold and indicates a rising edge in the ASK modulation. If V_(SD)goes below or meets V_(SLow), then the comparator circuit will determinethat the change in V_(Tx) meets the fall threshold and indicates afalling edge of the ASK modulation. It is to be noted that V_(SUp) andV_(SLo) may be selected to ensure a symmetrical triggering.

In some examples, such as the comparator circuit 74 illustrated in FIG.6, the comparator circuit 74 may comprise a window comparator circuit.In such examples, the V_(SUp) and V_(SLo) may be set as a fraction ofthe power supply determined by resistor values of the comparator circuit74. In some such examples, resistor values in the comparator circuit maybe configured such that

${V_{Sup} = {V_{in}\left\lbrack \frac{R_{U2}}{R_{U1} + R_{U2}} \right\rbrack}}{V_{SLo} = {V_{in}\left\lbrack \frac{R_{L2}}{R_{L1} + R_{L2}} \right\rbrack}}$where Vin is a power supply determined by the comparator circuit 74.When V_(SD) exceeds the set limits for V_(Sup) or V_(SLo), thecomparator circuit 74 triggers and pulls the output (V_(Cout)) low.

Further, while the output of the comparator circuit 74 could be outputto the transmission controller 28 and utilized to decode the wirelessdata signals by signaling the rising and falling edges of the ASKmodulation, in some examples, the SR latch 76 may be included to addnoise reduction and/or a filtering mechanism for the slope detector 72.The SR latch 76 may be configured to latch the signal (Plot C) in asteady state to be read by the transmitter controller 28, until a resetis performed. In some examples, the SR latch 76 may perform functions oflatching the comparator signal and serve as an inverter to create anactive high alert out signal. Accordingly, the SR latch 76 may be any SRlatch known in the art configured to sequentially excite when the systemdetects a slope or other modulation excitation. As illustrated, the SRlatch 76 may include NOR gates, wherein such NOR gates may be configuredto have an adequate propagation delay for the signal. For example, theSR latch 76 may include two NOR gates (NOR_(Up), NOR_(Lo)), each NORgate operatively associated with the upper voltage output 78 of thecomparator 74 and the lower voltage output 79 of the comparator 74.

In some examples, such as those illustrated in Plot C, a reset of the SRlatch 76 is triggered when the comparator circuit 74 outputs detectionof V_(SUp) (solid plot on Plot C) and a set of the SR latch 76 istriggered when the comparator circuit 74 outputs V_(SLo) (dashed plot onPlot C). Thus, the reset of the SR latch 76 indicates a falling edge ofthe ASK modulation and the set of the SR latch 76 indicates a risingedge of the ASK modulation. Accordingly, as illustrated in Plot D, therising and falling edges, indicated by the demodulation circuit 70, areinput to the transmission controller 28 as alerts, which are decoded todetermine the received wireless data signal transmitted, via the ASKmodulation, from the wireless receiver system(s) 30.

The incoming signal VTX exemplified in the plots of FIG. 8 does not leadto excess bias or saturation because the values of V_(BIAS) and V_(G)are at appropriate levels, but the coupling environment may change(e.g., from strong to weak coupling), such that the existing V_(BIAS)and V_(G) are no longer appropriate and would no longer allow accuratesignal detection. However, automatic gain and bias routines are appliedas described herein to continually evaluate the system behavior and setV_(BIAS) and V_(G) such that accurate signal detection is providedthroughout the range of allowable coupling strengths.

Referring now to FIG. 9, and with continued reference to FIGS. 1-4, ablock diagram illustrating an embodiment of the power conditioningsystem 40 is illustrated. At the power conditioning system 40,electrical power is received, generally, as a DC power source, via theinput power source 12 itself or an intervening power converter,converting an AC source to a DC source (not shown). A voltage regulator46 receives the electrical power from the input power source 12 and isconfigured to provide electrical power for transmission by the antenna21 and provide electrical power for powering components of the wirelesstransmission system 21. Accordingly, the voltage regulator 46 isconfigured to convert the received electrical power into at least twoelectrical power signals, each at a proper voltage for operation of therespective downstream components: a first electrical power signal toelectrically power any components of the wireless transmission system 20and a second portion conditioned and modified for wireless transmissionto the wireless receiver system 30. As illustrated in FIG. 3, such afirst portion is transmitted to, at least, the sensing system 50, thetransmission controller 28, and the communications system 29; however,the first portion is not limited to transmission to just thesecomponents and can be transmitted to any electrical components of thewireless transmission system 20.

The second portion of the electrical power is provided to an amplifier42 of the power conditioning system 40, which is configured to conditionthe electrical power for wireless transmission by the antenna 21. Theamplifier may function as an inverter, which receives an input DC powersignal from the voltage regulator 46 and generates an AC as output,based, at least in part, on PWM input from the transmission controlsystem 26. The amplifier 42 may be or include, for example, a powerstage invertor, such as a single field effect transistor (FET), a dualfield effect transistor power stage invertor or a quadruple field effecttransistor power stage invertor. The use of the amplifier 42 within thepower conditioning system 40 and, in turn, the wireless transmissionsystem 20 enables wireless transmission of electrical signals havingmuch greater amplitudes than if transmitted without such an amplifier.For example, the addition of the amplifier 42 may enable the wirelesstransmission system 20 to transmit electrical energy as an electricalpower signal having electrical power from about 10 mW to about 500 W. Insome examples, the amplifier 42 may be or may include one or moreclass-E power amplifiers. Class-E power amplifiers are efficiently tunedswitching power amplifiers designed for use at high frequencies (e.g.,frequencies from about 1 MHz to about 1 GHz). Generally, a single-endedclass-E amplifier employs a single-terminal switching element and atuned reactive network between the switch and an output load (e.g., theantenna 21). Class E amplifiers may achieve high efficiency at highfrequencies by only operating the switching element at points of zerocurrent (e.g., on-to-off switching) or zero voltage (off to onswitching). Such switching characteristics may minimize power lost inthe switch, even when the switching time of the device is long comparedto the frequency of operation. However, the amplifier 42 is certainlynot limited to being a class-E power amplifier and may be or may includeone or more of a class D amplifier, a class EF amplifier, an H invertoramplifier, and/or a push-pull invertor, among other amplifiers thatcould be included as part of the amplifier 42.

Turning now to FIG. 10 and with continued reference to, at least, FIGS.1 and 2, the wireless receiver system 30 is illustrated in furtherdetail. The wireless receiver system 30 is configured to receive, atleast, electrical energy, electrical power, electromagnetic energy,and/or electrically transmittable data via near field magnetic couplingfrom the wireless transmission system 20, via the transmission antenna21. As illustrated in FIG. 9, the wireless receiver system 30 includes,at least, the receiver antenna 31, a receiver tuning and filteringsystem 34, a power conditioning system 32, a receiver control system 36,and a voltage isolation circuit 70. The receiver tuning and filteringsystem 34 may be configured to substantially match the electricalimpedance of the wireless transmission system 20. In some examples, thereceiver tuning and filtering system 34 may be configured to dynamicallyadjust and substantially match the electrical impedance of the receiverantenna 31 to a characteristic impedance of the power generator or theload at a driving frequency of the transmission antenna 20.

As illustrated, the power conditioning system 32 includes a rectifier 33and a voltage regulator 35. In some examples, the rectifier 33 is inelectrical connection with the receiver tuning and filtering system 34.The rectifier 33 is configured to modify the received electrical energyfrom an alternating current electrical energy signal to a direct currentelectrical energy signal. In some examples, the rectifier 33 iscomprised of at least one diode. Some non-limiting exampleconfigurations for the rectifier 33 include, but are not limited toincluding, a full wave rectifier, including a center tapped full waverectifier and a full wave rectifier with filter, a half wave rectifier,including a half wave rectifier with filter, a bridge rectifier,including a bridge rectifier with filter, a split supply rectifier, asingle phase rectifier, a three phase rectifier, a voltage doubler, asynchronous voltage rectifier, a controlled rectifier, an uncontrolledrectifier, and a half controlled rectifier. As electronic devices may besensitive to voltage, additional protection of the electronic device maybe provided by clipper circuits or devices. In this respect, therectifier 33 may further include a clipper circuit or a clipper device,which is a circuit or device that removes either the positive half (tophalf), the negative half (bottom half), or both the positive and thenegative halves of an input AC signal. In other words, a clipper is acircuit or device that limits the positive amplitude, the negativeamplitude, or both the positive and the negative amplitudes of the inputAC signal.

Some non-limiting examples of a voltage regulator 35 include, but arenot limited to, including a series linear voltage regulator, a buckconvertor, a low dropout (LDO) regulator, a shunt linear voltageregulator, a step up switching voltage regulator, a step down switchingvoltage regulator, an inverter voltage regulator, a Zener controlledtransistor series voltage regulator, a charge pump regulator, and anemitter follower voltage regulator. The voltage regulator 35 may furtherinclude a voltage multiplier, which is as an electronic circuit ordevice that delivers an output voltage having an amplitude (peak value)that is two, three, or more times greater than the amplitude (peakvalue) of the input voltage. The voltage regulator 35 is in electricalconnection with the rectifier 33 and configured to adjust the amplitudeof the electrical voltage of the wirelessly received electrical energysignal, after conversion to AC by the rectifier 33. In some examples,the voltage regulator 35 may an LDO linear voltage regulator; however,other voltage regulation circuits and/or systems are contemplated. Asillustrated, the direct current electrical energy signal output by thevoltage regulator 35 is received at the load 16 of the electronic device14. In some examples, a portion of the direct current electrical powersignal may be utilized to power the receiver control system 36 and anycomponents thereof; however, it is certainly possible that the receivercontrol system 36, and any components thereof, may be powered and/orreceive signals from the load 16 (e.g., when the load 16 is a batteryand/or other power source) and/or other components of the electronicdevice 14.

The receiver control system 36 may include, but is not limited toincluding, a receiver controller 38, a communications system 39 and amemory 37. The receiver controller 38 may be any electronic controlleror computing system that includes, at least, a processor which performsoperations, executes control algorithms, stores data, retrieves data,gathers data, controls and/or provides communication with othercomponents and/or subsystems associated with the wireless receiversystem 30. The receiver controller 38 may be a single controller or mayinclude more than one controller disposed to control various functionsand/or features of the wireless receiver system 30. Functionality of thereceiver controller 38 may be implemented in hardware and/or softwareand may rely on one or more data maps relating to the operation of thewireless receiver system 30. To that end, the receiver controller 38 maybe operatively associated with the memory 37. The memory may include oneor both of internal memory, external memory, and/or remote memory (e.g.,a database and/or server operatively connected to the receivercontroller 38 via a network, such as, but not limited to, the Internet).The internal memory and/or external memory may include, but are notlimited to including, one or more of a read only memory (ROM), includingprogrammable read-only memory (PROM), erasable programmable read-onlymemory (EPROM or sometimes but rarely labelled EROM), electricallyerasable programmable read-only memory (EEPROM), random access memory(RAM), including dynamic RAM (DRAM), static RAM (SRAM), synchronousdynamic RAM (SDRAM), single data rate synchronous dynamic RAM (SDRSDRAM), double data rate synchronous dynamic RAM (DDR SDRAM, DDR2, DDR3,DDR4), and graphics double data rate synchronous dynamic RAM (GDDRSDRAM, GDDR2, GDDR3, GDDR4, GDDR5), a flash memory, a portable memory,and the like. Such memory media are examples of nontransitory computerreadable memory media.

Further, while particular elements of the receiver control system 36 areillustrated as subcomponents and/or circuits (e.g., the memory 37, thecommunications system 39, among other contemplated elements) of thereceiver control system 36, such components may be external of thereceiver controller 38. In some examples, the receiver controller 38 maybe and/or include one or more integrated circuits configured to includefunctional elements of one or both of the receiver controller 38 and thewireless receiver system 30, generally. As used herein, the term“integrated circuits” generally refers to a circuit in which all or someof the circuit elements are inseparably associated and electricallyinterconnected so that it is considered to be indivisible for thepurposes of construction and commerce. Such integrated circuits mayinclude, but are not limited to including, thin-film transistors,thick-film technologies, and/or hybrid integrated circuits.

FIG. 11 illustrates an example, non-limiting embodiment of one or bothof the transmitter antenna 21 and/or the receiver antenna 31 that may beused with any of the systems, methods, and/or apparatus disclosedherein. In the illustrated embodiment, the antenna 21, 31, is a flatspiral coil configuration. Non-limiting examples can be found in U.S.Pat. Nos. 9,941,743, 9,960,628, 9,941,743 all to Peralta et al.; U.S.Pat. Nos. 9,948,129, 10,063,100 to Singh et al.; U.S. Pat. No. 9,941,590to Luzinski; U.S. Pat. No. 9,960,629 to Rajagopalan et al.; and U.S.Patent App. Nos. 2017/0040107, 2017/0040105, 2017/0040688 to Peralta etal.; all of which are assigned to the assignee of the presentapplication and incorporated fully herein by reference.

In addition, the antenna 21, 31 may be constructed having amulti-layer-multi-turn (MLMT) construction in which at least oneinsulator is positioned between a plurality of conductors. Non-limitingexamples of antennas having an MLMT construction that may beincorporated within the wireless transmission system(s) 20 and/or thewireless receiver system(s) 30 may be found in U.S. Pat. Nos. 8,610,530,8,653,927, 8,680,960, 8,692,641, 8,692,642, 8,698,590, 8,698,591,8,707,546, 8,710,948, 8,803,649, 8,823,481, 8,823,482, 8,855,786,8,898,885, 9,208,942, 9,232,893, and 9,300,046 to Singh et al., all ofwhich are assigned to the assignee of the present application areincorporated fully herein. These are merely exemplary antenna examples;however, it is contemplated that the antennas 31 may be any antennacapable of the aforementioned higher power, high frequency wirelesspower transfer.

The automatic gain and bias control described herein may significantlyreduce the BOM for the demodulation circuit, and the wirelesstransmission system as a whole, by allowing usage of cheaper, lesscomputationally capable processor(s) for or with the transmissioncontroller. The throughput and accuracy of an edge-detection codingscheme depends in large part upon the system's ability to quickly andaccurately detect signal slope changes. These constraints may be bettermet in environments wherein the distance between, and orientations of,the sender and receiver change dynamically, or the magnitude of thereceived power signal and embedded data signal may change dynamically,via the disclosed automatic gain and bias control. This may allowreading of faint signals via appropriate gain, for example, while alsoavoiding saturation with respect to larger signals.

The systems, methods, and apparatus disclosed herein are designed tooperate in an efficient, stable and reliable manner to satisfy a varietyof operating and environmental conditions. The systems, methods, and/orapparatus disclosed herein are designed to operate in a wide range ofthermal and mechanical stress environments so that data and/orelectrical energy is transmitted efficiently and with minimal loss. Inaddition, the system 10 may be designed with a small form factor using afabrication technology that allows for scalability, and at a cost thatis amenable to developers and adopters. In addition, the systems,methods, and apparatus disclosed herein may be designed to operate overa wide range of frequencies to meet the requirements of a wide range ofapplications.

In an embodiment, a ferrite shield may be incorporated within theantenna structure to improve antenna performance. Selection of theferrite shield material may be dependent on the operating frequency asthe complex magnetic permeability (μ=μ′−j*μ″) is frequency dependent.The material may be a polymer, a sintered flexible ferrite sheet, arigid shield, or a hybrid shield, wherein the hybrid shield comprises arigid portion and a flexible portion. Additionally, the magnetic shieldmay be composed of varying material compositions. Examples of materialsmay include, but are not limited to, zinc comprising ferrite materialssuch as manganese-zinc, nickel-zinc, copper-zinc, magnesium-zinc, andcombinations thereof.

As used herein, the phrase “at least one of” preceding a series ofitems, with the term “and” or “or” to separate any of the items,modifies the list as a whole, rather than each member of the list (i.e.,each item). The phrase “at least one of” does not require selection ofat least one of each item listed; rather, the phrase allows a meaningthat includes at least one of any one of the items, and/or at least oneof any combination of the items, and/or at least one of each of theitems. By way of example, the phrases “at least one of A, B, and C” or“at least one of A, B, or C” each refer to only A, only B, or only C;any combination of A, B, and C; and/or at least one of each of A, B, andC.

The predicate words “configured to”, “operable to”, and “programmed to”do not imply any particular tangible or intangible modification of asubject, but, rather, are intended to be used interchangeably. In one ormore embodiments, a processor configured to monitor and control anoperation or a component may also mean the processor being programmed tomonitor and control the operation or the processor being operable tomonitor and control the operation. Likewise, a processor configured toexecute code can be construed as a processor programmed to execute codeor operable to execute code.

A phrase such as “an aspect” does not imply that such aspect isessential to the subject technology or that such aspect applies to allconfigurations of the subject technology. A disclosure relating to anaspect may apply to all configurations, or one or more configurations.An aspect may provide one or more examples of the disclosure. A phrasesuch as an “aspect” may refer to one or more aspects and vice versa. Aphrase such as an “embodiment” does not imply that such embodiment isessential to the subject technology or that such embodiment applies toall configurations of the subject technology. A disclosure relating toan embodiment may apply to all embodiments, or one or more embodiments.An embodiment may provide one or more examples of the disclosure. Aphrase such an “embodiment” may refer to one or more embodiments andvice versa. A phrase such as a “configuration” does not imply that suchconfiguration is essential to the subject technology or that suchconfiguration applies to all configurations of the subject technology. Adisclosure relating to a configuration may apply to all configurations,or one or more configurations. A configuration may provide one or moreexamples of the disclosure. A phrase such as a “configuration” may referto one or more configurations and vice versa.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” or as an “example” is not necessarily to be construed aspreferred or advantageous over other embodiments. Furthermore, to theextent that the term “include,” “have,” or the like is used in thedescription or the claims, such term is intended to be inclusive in amanner similar to the term “comprise” as “comprise” is interpreted whenemployed as a transitional word in a claim. Furthermore, to the extentthat the term “include,” “have,” or the like is used in the descriptionor the claims, such term is intended to be inclusive in a manner similarto the term “comprise” as “comprise” is interpreted when employed as atransitional word in a claim.

All structural and functional equivalents to the elements of the variousaspects described throughout this disclosure that are known or latercome to be known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe claims. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the claims. No claim element is to be construedunder the provisions of 35 U.S.C. § 112, sixth paragraph, unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

Reference to an element in the singular is not intended to mean “one andonly one” unless specifically so stated, but rather “one or more.”Unless specifically stated otherwise, the term “some” refers to one ormore. Pronouns in the masculine (e.g., his) include the feminine andneuter gender (e.g., her and its) and vice versa. Headings andsubheadings, if any, are used for convenience only and do not limit thesubject disclosure.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of what may be claimed, but ratheras descriptions of particular implementations of the subject matter.Certain features that are described in this specification in the contextof separate embodiments can also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment can also be implemented in multipleembodiments separately or in any suitable sub-combination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to a subcombination or variation of a sub combination.

What is claimed is:
 1. A wireless power transmission system comprising:a transmitter antenna configured to couple with at least one otherantenna of at least one other system and transmit alternating current(AC) wireless signals to the at least one other antenna, the AC wirelesssignals including wireless power signals and wireless data signals, thewireless data signals generated by altering electrical characteristicsof the AC wireless signals at the at least one other system; at leastone sensor configured to detect electrical information associated withthe electrical characteristics of the AC wireless signals, theelectrical information including one or more of a current of the ACwireless signals, a voltage of the AC wireless signals and a power levelof the AC wireless signals; a demodulation circuit configured to (i)receive the electrical information from the at least one sensor, (ii)apply automatic bias control and gain control to the electricalinformation to generate a modified electrical information signal (iii)detect a change in the modified electrical information signal, (iv)determine if the change in the modified electrical information signalmeets or exceeds one of a rise threshold or a fall threshold, (v) if thechange exceeds one of the rise threshold or the fall threshold, generatean alert, (vi) and output a plurality of data alerts; a transmittercontroller configured to (i) receive the plurality of data alerts fromthe demodulation circuit, and (ii) decode the plurality of data alertsinto the wireless data signals.
 2. The wireless power transmissionsystem of claim 1, wherein the demodulation circuit includes a slopedetection circuit, and wherein the slope detection circuit comprises afirst opamp (operational amplifier) for slope detection to produce aslope detection signal and a second opamp for amplification of the slopedetection signal to generate an amplified slope detection signal.
 3. Thewireless power transmission system of claim 2, wherein an offset voltagesignal is supplied to the first opamp, the offset voltage signal beingcontrolled by a first digital potentiometer within a first voltagedivider, and wherein an amplification control signal is supplied to thesecond opamp, the amplification control signal being controlled by asecond digital potentiometer within a second voltage divider.
 4. Thewireless power transmission system of claim 3, wherein respectiveresistance values of the first digital potentiometer and the seconddigital potentiometer are set by the transmitter controller.
 5. Thewireless power transmission system of claim 4, wherein the transmittercontroller sets the respective resistance values of the first digitalpotentiometer and the second digital potentiometer based on sensedcurrent associated with the wireless data signals and sensed couplingstrength between the transmitter antenna and the at least one otherantenna.
 6. The wireless power transmission system of claim 1, whereinthe electrical characteristics include a voltage of the wireless powersignals, and wherein the demodulation circuit is configured to detect achange in the modified electrical information signal by determining avoltage rate of change of a voltage of the modified electricalinformation signal.
 7. The wireless power transmission system of claim6, wherein the demodulation circuit includes a comparator circuitconfigured to (i) receive the voltage rate of change, (ii) compare thevoltage rate of change to a rising rate of change, and (iii) determinethat the change in the modified electrical information signal meets orexceeds the rise threshold, if the voltage rate of change meets orexceeds the rising rate of change.
 8. The wireless power transmissionsystem of claim 6, wherein the demodulation circuit includes acomparator circuit configured to (i) receive the voltage rate of change,(ii) compare the voltage rate of change to a falling rate of change, and(iii) determine that the change in the modified electrical informationsignal meets or exceeds the fall threshold, if the voltage rate ofchange meets or exceeds the falling rate of change.
 9. The wirelesspower transmission system of claim 6, wherein the demodulation circuitincludes a comparator circuit configured to (i) receive the voltage rateof change, (ii) compare the voltage rate of change to a rising rate ofchange, (iii) determine that the change in the modified electricalinformation signal meets or exceeds the rise threshold, if the voltagerate of change meets or exceeds the rising rate of change, (iv) comparethe voltage rate of change to a falling rate of change, and (v)determine that the change in the electrical characteristics meets orexceeds the fall threshold, if the voltage rate of change meets orexceeds the falling rate of change.
 10. The wireless power transmissionsystem of claim 9, wherein the demodulation circuit includes a set/reset(SR) latch in operative communication with an output of the comparatorcircuit.
 11. The wireless power transmission system of claim 1, whereinthe transmission antenna is configured to operate based on an operatingfrequency of about 6.78 MHz.
 12. A demodulation circuit for a wirelesspower transmission system, the wireless power transmission systemconfigured to transmit wireless power signals, the demodulation circuitcomprising: a slope detector circuit configured to determine a voltagerate of change for a voltage of the wireless power signals; and acomparator circuit configured to (i) receive the voltage rate of change,(ii) apply automatic bias control and gain control to the voltage rateof change to generate a modified voltage rate of change (ii) compare themodified voltage rate of change to a rising rate of change, (iii)determine if the modified voltage rate of change meets or exceeds arising rate of change, (iv) compare the modified voltage rate of changeto a falling rate of change, (v) determine if the modified voltage rateof change of change meets or exceeds the falling rate of change and (vi)if the modified voltage rate of change exceeds the rising or fallingrate of change, generate an alert.
 13. A method of demodulating data ina wireless transmission system comprising: coupling a transmitterantenna with at least one other antenna of at least one other system;transmitting alternating current (AC) wireless signals from thetransmitter antenna to the at least one other antenna, the AC wirelesssignals including wireless power signals and wherein wireless datasignals are superimposed on the AC wireless signals by alteringelectrical characteristics of the AC wireless signals at the at leastone other system to generate modified AC wireless signals; detectingelectrical information associated with electrical characteristics of themodified AC wireless signals, the electrical information including oneor more of a current of the modified AC wireless signals, a voltage ofthe modified AC wireless signals and a power level of the modified ACwireless signals; receiving the electrical information; applyingautomatic bias control and gain control to the electrical information togenerate a modified electrical information signal; detecting a change inthe modified electrical information signal; determining if the change inthe modified electrical information signal meets or exceeds one of arise threshold or a fall threshold; generating a data alert if thechange exceeds one of the rise threshold or the fall threshold;outputting a plurality of data alerts; receiving the plurality of dataalerts; and decoding the plurality of data alerts into the wireless datasignals.
 14. The method of claim 13, wherein detecting the change in themodified electrical information signal comprises sensing an output of aslope detection circuit, the slope detection circuit having a firstopamp (operational amplifier) for slope detection to produce a slopedetection signal and a second opamp for amplification of the slopedetection signal to generate an amplified slope detection signal. 15.The method of claim 14, wherein applying the automatic bias control andgain control to the electrical information to generate the modifiedelectrical information signal comprises applying an offset voltagesignal to the first opamp, the offset voltage signal being controlled bya first digital potentiometer within a first voltage divider, andapplying an amplification control signal to the second opamp, theamplification control signal being controlled by a second digitalpotentiometer within a second voltage divider.
 16. The method of claim15, further comprising setting the respective resistance values of thefirst digital potentiometer and the second digital potentiometer via atransmitter controller based on sensed current associated with thewireless data signals and sensed coupling strength between thetransmitter antenna and the at least one other antenna.
 17. The methodof claim 13, wherein detecting the change in the modified electricalinformation signal comprises determining a voltage rate of change of avoltage of the modified electrical information signal.
 18. The method ofclaim 17, wherein determining if the change in the modified electricalinformation signal meets or exceeds one of the rise threshold or thefall threshold includes comparing the voltage rate of change to a risingrate of change, determining that the change in the modified electricalinformation signal meets or exceeds the rise threshold, if the voltagerate of change meets or exceeds the rising rate of change, comparing thevoltage rate of change to a falling rate of change, and determining thatthe change in the modified electrical information signal meets orexceeds the fall threshold, if the voltage rate of change meets orexceeds the falling rate of change.
 19. The method of claim 13, whereindecoding the plurality of data alerts into the wireless data signalscomprises passing the plurality of data alerts through at least oneset/reset (SR) latch.
 20. The method of with claim 13, whereintransmitting AC wireless signals from the transmitter comprisestransmitting at an operating frequency of about 6.78 MHz.